Note: Descriptions are shown in the official language in which they were submitted.
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N-OXIDES AS NKl RECEPTOR ANTAGONIST PRODRUGS OF 4-PHENYL-PYRIDINE DERIVATIVES
The present invention relates to N-oxides of compounds of the general formula
I (R2 >n
R ~ O
x I R3 R3' Ra
R O N
R4,/ I
wherein
R is hydrogen, lower alkyl, lower all:oxy, halogen or trifluoromethyl;
R1 is hydrogen or halogen; or
R and R' may be together with the ring carbon atoms to which they are attached
-CH=CH-CH=CH-;
R` and Rz are independently from each other hydrogen, halogen,
trifluoromethyl, lower
alkoxy or cyano; or
io R'` and Rz may be together -CH=CH-CH=CH-, optionally substituted by one or
two
substituents selected from lower alkyl or lower alkoxy;
Rj, R;' are independently from each other hydrogen, lower alkyl or cycloalkyl;
R4, R4 are independently from each other -(CH2)mOR6 or lower alkyl;
or
Wand R4 form together with the N-atom to which they are attached a cyclic
tertiary amine
of the group
R5~/
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R5 is hydrogen, hydroxy, lower alkyl, -lower alkoxy, =(CHZ)mOH, -COOR3,
-CON(R3)2 , -N(R3)CO-lower alkyl or -C(O)R3;
R6 is hydrogen, lower alkyl or phenyl;
X is -C(O)N(R6)- , -N(R6)C(O)-, -(CH2)m0- or -O(CHZ)n,-;
~
n is 0, 1, 2, 3 or 4; and
m is 1, 2 or 3;
and to pharmaceutically acceptable acid addition salts thereof.
It has been found that these N-oxides of the present invention have an in
vitro
activity on the NK1 receptor and/or may be used as prodrugs of compounds of
formula
~R1 ~n
I / (RZ ~n
R
~ I
X
,
\
~ R3 R3' Rz
R\N \N
R4~ I I which are antagonists of the Neurokinin 1(NK-1, substance P) receptor.
However, the advantage of a prodrug lies in its physical properties, such as
enhanced
water solubility for parenteral administration compared to the parent drug, or
it enhances
absorption from the digestive tract, or it may enhance dn.ig stability for
long-term storage.
Compounds of formula II have limited water solubility, not allowing bolus
injections. It
was therefore useful to find derivatives of the compound of formula II to
render these
compounds suitable for parenteral and intramuscular application. It has been
shown that
N-oxides of compounds of formula I fi.ilfil all requirements of a good
prodrug.
A prodrug is in most cases a pharmacologically inactive derivative of a parent
drug
molecule that requires spontaneous or enzymatic transformation within the body
in order
to release the active drug, and that has improved delivery properties over the
parent drug
molecule. It has been shown that a molecule with optimal structural
configuration and
physicochemical properties for eliciting the desired therapeutic response at
its target site
does not necessarily possess the best molecular form and properties for its
delivery to its
point of ultimate action. Usually, only a minor fraction of doses administered
reach the
target area and since most agents interact with non-target sites as well, an
inefficient
delivery may result in undesirable side effects. This fact of differences in
transport and in
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-3-
situ effect characteristics for many drug molecules is the basic reason why
bioreversible
chemical derivatization of drugs, i.e., prodrug formation is a means by which
a substantial
improvement in the overall efficacy of drugs can often be achieved. Prodrugs
are designed
to overcome pharmaceutically and/or pharmacokinetically based problems
associated with
the parent drug molecule that would otherwise limit the clinical usefulness of
the drug.
i
In recent years several types of bioreversible derivatives have been exploited
for
utilization in designing prodrugs. Using esters as a prodrug type for drugs
containing
carboxyl or hydroxyl function is most popular. Further well-known are prodrug
derivatives
of peptides, 4-imidazolidinones and the lilce, described in Drugs of the
Future, 1991, 16(5),
443-458 or N-oxides, described for example in US 5.691.336.
As mentioned earlier, the compounds of formula II are antagonists of the
neurokinin
receptor. The central and peripheral actions of the mammalian tachykinin
substance P
have been associated with numerous inflammatory conditions including migraine,
rheumatoid arthritis, asthma, and inflammatory bowel disease as well as
mediation of the
emetic reflex and the modulation of central nervous system (CNS) disorders
such as
Parkinson's disease (Neurosci. Res., 1996, 7, 187-214), anxiety (Can. J.
Phys., 1997, 75,
612-621) and depression (Science, 1998, 281, 1640-1645).
Evidence for the usefiilness of tachykinin receptor antagonists in pain,
headache,
especially migraine, Alzheimer's disease, multiple sclerosis, attenuation of
morphine
withdrawal, cardiovascular changes, oedema, such as oedema caused by thermal
injury,
chronic inflammatory diseases such as rheumatoid arthritis, asthma/bronchial
hyperreactivity and other respiratory diseases including allergic rhinitis,
inflammatory
diseases of the gut including ulcerative colitis and Crohn's disease, ocular
injury and ocular
inflammatory diseases reviewed in "Tachykinin Receptor and Tachykinin Receptor
Antagonists", J. Auton. Pharmacol., 13, 23-93, 1993.
Furthermore, Neurokinin 1 receptor antagonists are being developed for the
treatment of a number of physiological disorders associated with an excess or
imbalance of
tachykinin, in particular substance P. Examples of conditions in which
substance P has
been implicated include disorders of the central nervous system such as
anxiety, depression
3o and psychosis (WO 95/16679, WO 95/18124 and WO 95/23798).
The neurokinin-1 receptor antagonists are further useful for the treatment of
motion
sickness and for treatment induced vomiting.
In addition, in The New England Journal of Medicine, Vol. 340, No. 3 190-195,
1999
has been described the reduction of cisplatin-induced emesis by a selective
neurokinin-l-
receptor antagonist.
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The usefulness of neurokinin 1 receptor antagonists for the treatment of
certain
forms of urinary incontinence is further described in Neuropeptides, 32(1), 1-
49, (1998)
and Eur. J. Pharmacol., 383(3), 297-303, (1999).
Furthermore, US 5,972,938 describes a method for treating a psychoimmunologic
or
a psychosomatic disorder by administr~tion of a tachykinin receptor, such as
NK-1
receptor antagonist.
Objects of the present invention are the compounds of formula I and pharma-
ceutically acceptable salts thereof, the preparation of the above-mentioned
compounds,
medicaments containing them and their manufacture as well as the use of the
above-
1o mentioned compounds in the control or prevention of illnesses, especially
of illnesses and
disorders of the kind referred to earlier or in the manufacture of
corresponding
medicaments.
The most preferred indications in accordance with the present invention are
those,
which include disorders of the central nervous system, for example the
treatment or
prevention of certain depressive disorders or emesis by the administration of
NK-1
receptor antagonists. A major depressive episode has been defined as being a
period of at
least two weeks during which, for most of the day and nearly every day, there
is either
depressed mood or the loss of interest or pleasure in all, or nearly all
activities.
The following definitions of the general terms used in the present description
apply
irrespective of whether the terms in question appear alone or in combination.
As used
herein, the term "lower a1kyP" denotes a straight- or branched-chain alkyl
group containing
from 1-7 carbon atoms, for example, methyl, ethyl, propyl, isopropyl, n-butyl,
i-butyl, t-
butyl and the like.
Preferred lower alkyl groups are groups with 1-4 carbon atoms.
The term "lower alkoxy" denotes a group wherein the alkyl residues are as
defined
above, and which is attached via an oxygen atom.
The term "halogen" denotes chlorine, iodine, fluorine and bromine.
The term "cycloalkyP" denotes a saturated carbocyclic group, containing 3-6
carbon
atoms.
The term "cyclic tertiary amine" denotes, for example, pyrrolidin-l-yl,
piperidin-l-
yl, piperazin-l-yl, morpholin-4-yl or 1,1-dioxo-thiomorpholin-4-yl.
Exemplary preferred are compounds, in which X is -C(O)N(R6)-, wherein R6 is
methyl, for example the following compounds:
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4-15- [ (3,5-bis-trifluoromethyl-benzyl)-methyl-carbamoyl] -4-o-tolyl-pyridin-
2-yl}-4-oxy-
piperazine-1-carboxylic acid tert-butyl ester,
5'-[ (3,5-bis-trifluoromethyl-benzyl)-methyl-carbamoyl] -4'-o-tolyl-l-oxy-
3,4,5,6-
tetrahydro-2H-[1,2']bipyridinyl-4-carboxylic acid ethyl ester,
(RS)-6-[3-(acetyl-methyl-amino)-1-oxo-pyrrolidin-1-yl]-N-(3,5-bis-
trifluoromethyl-
~
b enzyl) -N-methyl-4-o-tolyl-nicotinamide,
N-(3,5-bis-trifluoromethyl-benzyl)-N-methyl-6-(4-oxy-morpholin-4-yl)-4-o-tolyl-
nicotinamide,
N- ( 3,5-bis-trifluoromethyl-benzyl)-6-(1,1-dioxo-1 X 6-4-oxy-thiomorpholin-4-
yl)-N-
1o methyl-4-o-tolyl-nicotinamide,
N-(3,5-bis-trifluoromethyl-benzyl)-6-(4-formyl-l-oxy-piperazin-1 -yl)-N-methyl-
4-o-
tolyl-nicotinamide,
N-methyl-N-(2-methyl-naphthalen-l-ylmethyl)-6- (4-oxy-morpholin-4-yl)-4-o-
tolyl-
nicotinamide,
N-methyl-6-(4-oxy- morpholin-4-yl)-N-naphthalen-1-ylmethyl-4-o-tolyl-
nicotinamide,
N-(2-methoxy-naphthalen-l-ylmethyl)-N-methyl-6-(4-oxy-morpholin-4-yl)-4-o-
tolyl-
nicotinamide,
N-( 2-methoxy-benzyl)-N-methyl-6-(4-oxy-morpholin-4-yl)-4-o-tolyl-
nicotinamide,
N-( 5-chloro-2-methoxy-benzyl)-N-methyl-6-(4-oxy-morpholin-4-yl)-4-o-tolyl-
2o nicotinamide,
N- (2-chloro-5-methoxy-benzyl)-N-methyl-6-morpholin-4-yl-4-o-tolyl-
nicotinamide,
N-methyl-6- (4-oxy-morpholin-4-yl)-N-pentafluorophenylmethyl-4-o-tolyl-
nicotinamide,
N-methyl-6- ( 4-oxy-morpholin-4-yl) -N-naphthalen-2-ylmethyl-4-o-tolyl-
nicotinamide,
N- [2-methoxy-5-( 5-trifluoromethyl-tetrazol-l-yl)-benzyl] -N-methyl-6-(4-oxy-
morpholin-4-yl)-4-o-tolyl-nicotinamide,
N-(1,4-dimethoxy-naphthalen-2-ylmethyl)-N-methyl-6-(4-oxy-morpholin-4-yl)-4-o-
tolyl-nicotinamide or
5'-- [ (3,5-bis-trifluoromethyl-benzyl)-methyl-carbamoyl] 4-o-tolyl-l-oxy-
3,4,5,6-
tetrahydro-2H-[1,2']bipyridinyl-4-carboxylic acid.
Further preferred are compounds, in which X is -N(R6)-CO-, wherein R6 is
hydrogen or methyl.
Examples of such compounds are:
2-(3,5-bis-trifluoromethyl-phenyl)-N-methyl-N- [6-(4-oxy-morpholin-4-yl)-4-o-
tolyl-
pyridin-3-yl] -isobutyramide,
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2-( 3,5-bis-trifluoromethyl-phenyl)-N- [4- ( 2-chloro-phenyl)-6-(4-oxy-
morpholin-4-yl)-
pyridin-3-yl] -N-methyl-isobutyramide,
2-(3,5-bis-trifluoromethyl-phenyl)-N- [6-(4-oxy-morpholin-4-yl)-4-o-tolyl-
pyridin-3-yl] -
isobutyramide,
2-(3,5-bis-trifluoromethyl-phenyl)-N-[4'-(2-chloro-phenyl)-1-oxy-3,4,5,6-
tetrahydro-2H-
,
[ 1,2']bipyridinyl-5'-yl] -N-methyl-isobutyramide,
2-( 3,5-bis-trifluoromethyl-phenyl)-N-(6-oxy-dimethylamino-4-o-tolyl-pyridin-3-
yl)-N-
methyl-isobutyramide,
2-(3,5-bis-trifluoromethyl-phenyl)-N- [4-(2-chloro-phenyl)-6-oxy-dimethylamino-
pyridin-3-yl]-isobutyramide,
2-( 3,5-bis-trifluoromethyl-phenyl)-N-1-(4-hydroxy-l-oxy-4'-o-tolyl-3,4,5,6-
tetrahydro-
2H- [ 1,2' ] bipyridinyl-5'-yl)-N-methyl-isobutyramide,
2-(3,5-bis-trifluoromethyl-phenyl)-N-16- [ (2-hydroxy-ethyl)-1-oxy-methyl-
amino] -4-o-
tolyl-pyridin-3-yl} -N-methyl-isobutyramide,
(R)-2-(3,5-bis-trifluoromethyl-phenyl)-N-[6-(3-hydroxy-l-oxy-pyrrolidin-l-yl)-
4-o-
tolyl-pyridin-3-yl] -N-methyl-isobutyramide,
2-(3,5-bis-trifluoromethyl-phenyl)-N-methyl-N- [6-(4-oxy-morpholin-4-yl)-4-o-
tolyl-
pyridin-3-yl] -acetamide,
2-(3,5-dimethoxy-phenyl)-N-methyl-N- [6-(4-oxy-morpholin-4-yl)-4-o-tolyl-
pyridin-3-
yl] - acetamide or
2-(3-fluoro-5-trifluoromethyl-phenyl)-N-methyl-N- [6-(4-oxy-morpholin-4-yl)-4-
o-tolyl-
pyridin-3-yl]- acetamide.
The present compounds of formula I and their pharmaceutically acceptable salts
can
be prepared by methods known in the art, for example, by processes described
below,
which process comprises
a) oxidizing a compound of formula
~ (RZ
R ~ ~
X \l
/
a ~ R3 R3 RZ
R~N N
Ra/ I I
with a suitable oxidizing agent to give a compound of formula
CA 02415890 2008-02-21
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(R'
(RZ )"
R ~
X ~ I
~ R3 R3~ RZ
R ~~ N
R4'Z ~
wherein the substituents have the significances given above, and
if desired, converting the compound obtained into a pharmaceutically
acceptable acid
addition salt.
In accordance with this procedure, a compound of formula I may be prepared,
for
example, as follows: To a solution of 10 mmol of a compound of general formula
II in 50
ml of a suitable solvent such as dichloromethane is added under ice cooling a
solution of
mmol of a suitable oxidizing reagent such as 3-chloroperbenzoic acid in 50 ml
of a
suitable solvent such as dichloromethane. Stirring is continued for an
appropriate time
lo (typically 1 h to 24 h) at 0 C and reaction progress may be followed by
thin-layer-
chromatography. In cases in which product formation is too slow, the reaction
mixture
may be stirred at room temperature. After evaporation of the solvent products
of general
formula I can be isolated by flash-chromatography in 15 % to 85 % yield.
Further
purification of crystalline products may be achieved by recrystallization from
a suitable
solvent.
For this transformation other oxidizing reagents may be used instead of 3-
chloroperbenzoic acid. Those oxidizing reagents are familiar to any person
skilled in the art
such as dimethyldioxirane in acetone, hydrogenperoxide in acetic acid or
potassium
peroxymonosulfate in a suitable solvent such as water.
The salt formation is effected at room temperature in accordance with methods
which are known per se and which are familiar to any person skilled in the
art. Not only
salts with inorganic acids, but also salts with organic acids come into
consideration.
Hydrochlorides, hydrobromides, sulphates, nitrates, citrates, acetates,
maleates, succinates,
methan-sulphonates, p-toluenesulphonates and the like are examples of such
salts.
The following schemes 1-8 describe the processes for preparation of compounds
of
formula I in more detail. The starting materials are known compounds and may
be
prepared according to methods known in the art, for example in accordance with
methods,
described in EP publication 1,035,115.
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-8- '
In the schemes the following abbreviations have beein used:
PivCl pivaloyl chloride
THF tetrahydrofuran
TMEDA N,N,N',N'-tetramethylethylene diamine
DIPEA N-ethyldiisopropyl-amine
KHMDS potassium hexamethyldisilazide
Scheme 1
Fli
NH PivCl/NEt3 \ N
2 THF/EtzOH2 ` 1. BuLi,TMEDA
~ O -
III 0 C to rt R4~ R4. N' IV 2 IZ -78 C
R4~ R4 ~ N7"T
, (R )n \
(R )n I
I ~ /
H R Ie VI R II HCI~
\ N B(OH)2 ` \ N 900C
f i O I i O
R41- R4, N V Pd(P(Ph)314 R4~N 4 N VII
R
(R' )n \ (Ry)" \
1. HC(OMe~
R I/
R 130 C ~
~
\ NH2 2. LiAIH4 NH
~ i
R4-R4 N VI11 0 C R' R4 N IX
O ~ (R2)n (R1 )n \
~
I
cl R3 R'- RZ X R / I R3 R3' oxidizing agent
_ (v (R)n
\
DIPEA
H i O I
R4- R4. N Rz II-1
(R1 )n \
I /
R f R3 R3,
o+ \ N \ (R)n
0 ~
R4, R4 N Rr 1-1
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The definition of substituents is given above.
Scheme 2
O
/0 N
N RS~ J XI! I\ 0 Hz/Pd-C
~ H
0- ~ I J~
I ~ THF N PivCl/NEt3
CI N XI R50 XIII
H H
~
I 1
N
1. BuLi/TMEDA I \ N
N 2. 12, -78 C N O
~
RXIV R5.0 XV
R
(R' )n I n R1)
R y Vi R H I/
a(oH)z > \ N H_ C R
Pd[P(Ph)3ia O 90 C ~ NHz
80 C ~ N I i
Rs XVI ~ N
R5 XVII
1 1. HC(OCl-~)3 I ~R )n CI R3 R3
130 C / f ~ (R~n
~ R I C Rr X
2. BH3 THF \ NH ~
0 C DIPEA
N
R5 XVlil
R') R~)n
n
~
~
3 3'
R / I R3 Roxidizing agent R { R R
N z
I \ N I ~ (Rz)n ` OI + 1 / 0 I \ (R )n
N p Rz, ~ N Rz
R5 I I-2 R s I-2
The definition of substituents is given above.
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-10- '
Scheme 3
0
0 1. SOCI I\ N' 1. BuLi/TMEDA
'\ OH 2= MeNFI2 ` N H THF, -78 C->-35 C
CI N R-H Rs~ XX 2. IZ THF, -78 C
IXX ~ XII i
(R1)n
I (R)n ~
R \ I 0
\ N~ RUI \ N~ 1. KHMDS,THF
I N H B(oH)2 H
31- Rs~ Pd[P(Ph)3]4 s~ N 2. /(R~j"
~I R XXII ~ I
R~ Rs Rr X-1
(R1) " ~ I (R')" ~
\
3
R I\ 0 N
R3- (Ra ) oxidizing agent
~
30 R\ 0 R3 R3 (R')
~
"
N R
2 O+
R II-3 Rs
1-3
Z= CI, Br, I or OS(0)2C6H4 CH3
and the definition of the other substituents is given above.
CA 02415890 2008-02-21
11-
Scheme 4
(R' )(R)
~ \ \
1 R i VI {
R ~ O
I ~ OMe B(oH) :
~ OMe ->
R'-N N pd[P(Rh)314 4 base
R4' XXIII R-R4. N XXIV
(R) (R) (R)"
6
R O ~
rtHR
-~ R O R' R' XXVII
I~ OH SOCIZ I\ CI
a= - ~
R R N XXV R4 Ra N XXVI
/(R)n ~R~ )n
I
R ~ O R3 R3' (Rz ) oxidizing agent 3 3=
" R O R R (R2 )"
R'- N N I R 6 \ I O/ t Ne
R4. Rz Ra N+ N R \ 2.
i4. R
11-4 R 1-4
The definition of substituents is given above.
Scheme 5
(R~ )" (R)"
R 0 I T 1. NaH
, R / -,T
LiAIH4 2=
~ OMe ~ OH ~ (R)"
a Z, ~Rz
R-N4 N XXIV R -N N s a
R R4 XXVIII R R X-1
/(R~)" (R~)n
R I
/ R3 R3(R') R 9-,~O " oxidizing agent R )"
z
R4 N N R4 ~\ R
R 11-5 R4= 1=5
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Z is Cl, Br, I or -OS(O)2C6H4CH3 and the definition of the other substituents
is described
above.
Scheme 6
(R')n
O 1. I~ R XXX (R~n
/ M9CI 5H
N~ 2. AcOH I/ R XII
R _
CI N IXXX 3. / I H~
~
Cl CN CI N XXXI
CI CN
O
(R% (R' )n
R I/ 1. KHMDS R I/ R3 R3= Z
(R )n
/ 2 R 3 R 3 I I
/ N I H (R)" R\N RZ
XXI I Z
PO
R2- 1 1-3
X-1
(R~)n
oxidizing agent R , a
- R R
/ (RZ)n
5 0- I j I
R ~' \N Rz,
I-3
5 Z is Cl, Br, I or -OS(O)ZC6H4CH3 and the definition of the other
substituents is given
above.
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Scheme 7
(R~)n Ri )n
\
R I~ O R3 RT 5, R I~ O R3 R3.
\ \ RSXor (R )20 \ \
I~ I (~'2)n~ I , N I (~'Z)n
~ N N Rz' r N N RZ,
HN J II-6 Rs,N J II-7
Rl)n
\
oxidizing agent R I~ O R3 R3
rU N (Ra)n
N+ N Rz
R5,,,N J 1-6
RS is the group -C(O)R3 and the definition of the remaining substituents is
given above.
lo
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-14-
Scheme 8
(R,) \
R ~ O R3 RV
I
(R2)"
N N R
r
XXXIII
KHSO
(R1) I \ (R~) I \
R ~ O R3 RT ~ R ~ O R3 Ra,
N (R2)" N (R2)~
r'N N RZ 0= C N N R
0 p I I-8
XXXIV
(R1) \
R I/ 0 R3 RT
A
O- N (RZ),,
~ N+ N Ra,
O; S j
11 1-7
O
The definition of substituents is given above.
As mentioned earlier, the compounds of formula I and their pharmaceutically
usable
addition salts may be used as prodrugs of the parent compounds of formula II,
which
possess valuable pharmacological properties. These compounds are antagonists
of the
Neurokinin 1(NK-1, substance P) receptor.
Furthermore, in addition, some N-oxides of formula I have a good affinity to
the
NK1 receptor. For some preferred compounds the pKi value is in the range of
8.3 to 8.7.
These compounds were investigated in accordance with the tests given
hereinafter.
Binding assay (in vitro)
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The affinity of test compounds for the NKl receptor was evaluated at human NKl
receptors
in CHO cells infected with the human NKl receptor (using the Semliki virus
expression
system) and radiolabelled with [3 H] substance P(final concentration 0.6 nM).
Binding
assays were performed in HEPES buffer (50 mM, pH 7.4) containing BSA (0.04 %)
leupeptin (8 g / ml), MnC12 (3 mM) and phosphoramidon (2 M). Binding assays
consisted of 250 l of inembrane suspehsion (1.25 x 105 cells / assay tube),
0.125 l of
buffer of displacing agent and 125 l of [3 H]substance P. Displacement curves
were
determined with at least seven concentrations of the compound. The assay tubes
were
incubated for 60 min at room temperature after which time the tube contents
were rapidly
1o filtered under vacuum through GF/C filters presoaked for 60 min with PEI
(0.3 %) with 2 x
2 ml washes of HEPES buffer (50 mM, pH 7.4). The radioactivity retained on the
filters was
measured by scintillation counting. All assays were performed in triplicate in
at least 2
separate experiments.
The evidence, that the compounds of formula I may be used as prodrugs of their
parent compounds of formula II is shown in accordance with the description
given
hereinafter.
The conversion of N-oxide prodrugs to the corresponding parent compounds is
due
to a reduction mechanism and there is some evidence from the literature that
similar
reactions occur in vivo and are probably catalysed by hemoglobin, hence the
decision to
study both the stability in plasma and blood was taken. The presence of an
oxidant in the
work-up solution should help preventing the reduction of the N-oxides.
Conversiorz in plasma: 10 Ls of a 100 g/mL DMSO solution of the pro-drug
were added
to 1 mL plasma to reach a final concentration of 1[Lg/mL. The incubation was
performed
at 37 C and 8 aliquots were taken at different time points over 30 min. These
aliquots were
treated with 3 volumes of cold MeOH containing H2O2 (final concentration 10
lov/v) and
centrifuged at 3500 g for 20 min at 10 C. The supernatant was directly used
to determine
the drug levels by LC-MS-MS (HPLC chromatography on reversed phase column X-
Terra
MS C18 3.5 M 2.1 x 30 mm Waters at 40 C, using a polarity gradient
MCOH/Form.Ac.
1% 20/80 /MeOH; run time; 3.0 min; inj. Vol.: 10 L; Flow: 0.2 L/min and
MS/MS
detection on a PE Sciex API-2000 MS/MS spectrometer; ion source: Turbospray;
ionisation
mode: ESP+).
Conversion in fresh blood: The same procedure was used for the stability
studies in blood,
even if much more care had to be taken after treatment with the H202.
Sample stability (plasma and blood): The final matrix were first prepared
(plasma or blood
treated with 3 volumes of cold MeOH containing H202 - 10%v/v - and centrifuged
at 3500
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g for 20 min at 10 C) and then incubated at 37 C into two tubes; the pro-
drug or the drug
were then incubated and finally their concentration determined by LC-MS-MS as
described above.
The method used to stop the reaction in both plasma and blood was found to be
enough
reliable to perform the studies at least when the analysis was performed
immediately after
the incubations.
The half-life obtained for the conversion prodrug to drug in plasma are
reported in the
following table (Plasma sample preparation was found to be critical for exact
determination of values for tl/z):
tl/z (hours)
Example No. Dog plasma Human plasma Rat plasma
1 18 8 4
2 18 12 5
16 16 6 2
The stability in blood is much lower (tl/z < 30 min) and it was impossible to
determine a
precise value of tliZ . However we can conclude that there are no major
species difference
with respect with stability in blood and that the prodrugs are converted to
the desired
drugs in high yield. (> 90 %)
In accordance with the tests the compounds of formula I can function as
prodrugs of
their parent compounds of formula II.
The compounds of formula I as well as their pharmaceutically usable acid
addition
salts can be used as medicaments, e.g. in the form of pharmaceutical
preparations. The
pharmaceutical preparations can be administered orally, e.g. in the form of
tablets, coated
tablets, dragees, hard and soft gelatine capsules, solutions, emulsions or
suspensions. The
administration can, however, also be effected rectally, e.g. in the form of
suppositories, or
parenterally, e.g. in the form of injection solutions.
The compounds of formula I and their pharmaceutically usable acid addition
salts
can be processed with pharmaceutically inert, inorganic or organic excipients
for the
production of tablets, coated tablets, dragees and hard gelatine capsules.
Lactose, corn
starch or derivatives thereof, talc, stearic acid or its salts etc can be used
as such excipients
e.g. for tablets, dragees and hard gelatine capsules.
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Suitable excipients for soft gelatine capsules are e.g. vegetable oils, waxes,
fats, semi-
solid and liquid polyols etc.
Suitable excipients for the manufacture of solutions and syrups are e.g.
water,
polyols, saccharose, invert sugar, glucose etc.
~
Suitable excipients for injection solutions are e.g. water, alcohols, polyols,
glycerol,
vegetable oils etc.
Suitable excipients for suppositories are e.g. natural or hardened oils,
waxes, fats,
semi-liquid or liquid polyols etc.
Moreover, the pharmaceutical preparations can contain preservatives,
solubilizers,
lo stabilizers, wetting agents, emulsifiers, sweeteners, colorants,
flavorants, salts for varying
the osmotic pressure, buffers, masking agents or antioxidants. They can also
contain still
other therapeutically valuable substances.
The dosage can vary within wide limits and will, of course, be fitted to the
individual
requirements in each particular case. In general, in the case of oral
administration a daily
dosage of about 10 to 1000 mg per person of a compound of general formula I
should be
appropriate, although the above upper limit can also be exceeded when
necessary.
The following Examples illustrate the present invention without limiting it.
All
temperatures are given in degrees Celsius.
The preparation of compounds of formula I, starting with compounds of formula
II,
is described generically in the description. This oxidation procedure is
always the last step
to obtain the N-oxides of compounds of formula 1. A detailed description of
this last step is
specifically described in the following examples 1, 2 and 13. The N-oxidation
of the
remaining compounds 3 to 12 and 14 to 29 is generically described in
accordance with the
above mentioned description.
Example 1
2-(3,5-Bis-trifluoromethyl-phenyl)-N-methyl-N- [6-(4-oxy-morpholin-4-yl)-4-o-
tolyl-
pyridin-3-yl] -isobutyramide
a) 4-(5-Nitro-2_pyridyl)-mor holine
To a solution of 20 g(126 mmol) of 2-chloro-5-nitropyridine in 150 ml
tetrahydrofuran
were added dropwise 27 ml (315 mmol) morpholine within 10 min. The reaction
mixture
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was refluxed for additional2 h. After cooling to room temperature, the solvent
was
removed in vacuo and the residue was re-dissolved in 200 ml ethyl acetate. The
organic
phase was washed with 200 ml 1 N sodium bicarbonate solution, dried (magnesium
sulfate) and evaporated to give 27.3 g(quantitative) of the title compound as
a yellow solid.
M.p. 142-143 C.
b) 2,2-Dimethyl-N- ( 6-morpholin-4-yl-p)ridin-3-yl) -propionamide
To a solution of 27.3 g(126 mmol) of 4-(5-nitro-2-pyridyl)-morpholine in 600
ml
methanol were added 2.5 g of 10 % of palladium on activated charcoal. The
reaction
mixture was hydrogenated (room temperature to ca. 45 C, 1 bar) until the
theoretical
1o amount of hydrogen was taken up (about 3 h). The catalyst was filtered off
and was washed
twice with 100 ml portions o methanol. The filtrate was evaporated in vacaco
to give 22.6 g
of a purple oil which consisted to ca. 95 % of the desired aniline derivative
according to
analysis by thin layer chromatography.
This crude product was dissolved in a mixture of 240 ml tetrahydrofuran and 60
ml diethyl
ether. After cooling to 0 C, 26 ml (189 mmol) of triethylamine were added in
one portion.
Stirring was continued while 23 g(189 mmol) of pivaloyl chloride were added
dropwise
within a period of 10 min. The ice bath was removed and the reaction mixture
was stirred
for lh at room temperature. Then, the solvent was removed in vacuo and the
residue was
suspended in 200 ml 1 N sodium bicarbonate solution. The product was extracted
three
times with 200 ml portions of dichloromethane, dried (sodium sulfate) and
evaporated.
Recrystallization of the solid residue from ethyl acetate/hexane 1:8 gave 28.6
g(86 of
the title compound as white crystals.
MS m/e (%): 264 (M+H-', 100).
c) N-(4-Iodo-6-morpholin-4-yl-pyridin-3-yl)-2,2-dimethyl- ropionamide
A solution of 28.4 g(108 mmol) 2,2-dimethyl-N-(6-morpholin-4-yl-pyridin-3-yl)-
propionamide and 49 ml (324 mmol) N,N,N',N'-tetramethylethylenediamine under
argon
in 600 ml tetrahydrofuran was cooled in a dry ice bath to -78 C. Within lh,
202 ml (324
mmol) of a 1.6 N n-butyllithium solution in hexane were added dropwise. The
reaction
mixture was allowed to warm up to -35 C overnight. After cooling again to -78
C, 37 g
(146 mmol) iodine dissolved in 60 ml tetrahydrofuran were added dropwise
during 15
min. The dry ice bath was replaced by an ice bath and a solution of 90 g(363
mmol)
sodium thiosulfate pentahydrate in 250 ml water were added within 10 min when
the
temperature of the reaction mixture had reached 0 C. Then, 1000 ml diethyl
ether were
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added and the organic layer was separated. The aqueous layer was extracted
twice with 500
ml dichloromethane and the combined organiclayers were dried (magnesium
sulfate) and
evaporated. Flash chromatography gave 15.6 g(37 %) of the title compound as a
light
brown oil which crystallized upon standing at room temperature.
MS m/e (%): 389 (IvI+, 71), 358 (25), 304 (43), 57 (100).
d) 2,2-Dimethyl-N-(6-morpholin-4-yl-4-o-tolyl-pyridin-3-yl)-propionamide
A mixture of 3.50 g(9.0 mmol) N-(4-iodo-6-morpholin-4-yl-pyridin-3-yl)-2,2-
dimethyl-
propionamide, 35 ml toluene, 18 ml 2 N sodium carbonate solution, 312 mg (0.27
mmol)
tetrakis(triphenylphosphine)paIladium(0) and 1.34 g(9.9 mmol) o-tolylboronic
acid was
lo heated under argon at 80 C Eor 12 h. After cooling to room temperature,
the aqueous
phase was separated and washed rivice with ethyl acetate. The combined organic
layers
were was.hed with 50 mI brine, dried (sodium sulfate) and evaporated.
Purification by
flash-chromatography gave 3.23 g(quantitative) of the title compound as a
white foam.
MS m/e (%): 354 (M+Ht, 100).
e 6-Morgholin-4_yl-4-o-tolyl-p-yridin-3-ylamine
A suspension of 2.93 g(8.28 mmol) 2,2-dimethyl-N-(6-morpholin-4-yl-4-o-tolyl-
pyridin-
3-yl)-propionamide in 80 ml 3 N hydrochloric acid solution and 5 ml 1-propanol
was
heated to 90-95 C overnight. The reaction mixture was cooled to room
temperature,
washed with three 20 ml portions diethyl ether and filtered over celite The
filtrate was
2o diluted with 20 ml water and was adjusted to pH 7-8 by addition of 28 %
sodium
hydroxide soltttion tinder ice cooling. The product was extracted with four
100 ml portions
of dichloromethane. The combined organic layers were washed with 50 ml brine,
dried
(magnesium sulfate) and evaporated to give 2.31 g(quantitative) of the title
compound as
a white foam.
MS m/e (%): 269 (1V1+, 100).
f) Iylethvl-(6-mor holin-4-yl-4-o-tolvl-pyridin-3-yll-amine
A solution of 2.24 g(8.3 mmol) 6-morpholin-4-yl-4-o-tolyl-pyridin-3-ylamine in
17 rnl
trimethyl orthoformate and 3 drops trifluoroacetic acid was heated for 2 h at
130 C. The
reaction mixture was evaporated and dried in'vacuo for 30 min. The residual
oil was
dissolved in 5 ml tetrahydrofuran and was added dropwise under ice cooling to
630 mg
(16.6 mmol) lithium aluminum hydride in 20 ml tetrahydrofuran. The reaction
mixture
was stirred for lh at room temperature, cooled to 0 C again and acidified (pH
1-2) by
*Trade-mark
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addition of 28 % hydrochloric acid solution. After stirring'for 5 min, 28 lo
sodium
hydroxide solution was added to reach pH 10. The solution was filtered over
celite,
evaporated and purified by flash chromatography to give 1.56 g(66 %) of the
title
compound as a white foam.
MS m/e (%): 283 (M+, 100).
g) 2-(3,5-Bis-trifluoromethyl-phenyl)-N-methyl-N-(6-morpholin-4-yl-4-o-tolyl-
pyridin-
3-yl)-isobutyramide
A solution of 1.46 g(5.15 mmol) methyl-(6-morpholin-4-yl-4-o-tolyl-pyridin-3-
yl)-amine
and 1.32 ml (7.73 mmol) N-ethyldiisopropylamine in 15 ml dichloromethane was
cooled
1o in an ice bath and 1.8 g(5.67 mmol) 2-(3,5-bis-trifluoromethyl-phenyl)-2-
methyl-
propionyl chloride were added dropwise. The reaction mixture was warmed to 35-
40 C
for 3h, cooled to room temperature again and was stirred with 25 mi saturated
sodium
bicarbonate solution. The organic layer was separated and the aqueous phase
was extracted
with dichloromethane. The combined organic layers were dried (magnesium
sulfate) and
evaporated. The residue was purified by flash chromatography to give 2.9
g(quantitative)
of the title compound as white crystals. M.p. 131-132 C.
h) 2-(3,5-Bis-trifluoromethyl-phenyl)-N-methyl-N-[6-(4-o , -morpholin-4-yl)-4-
o-tolyl-
pyridin-3-yll -isobutXramide
To a solution of 5.0 g(8.84 mmol) 2-(3,5-bis-trifluoromethyl-phenyl)-N-methyl-
N-(6-
morpholin-4-yl-4-o-tolyl-pyridin-3-yl)-isobutyramide in 50 ml dichloromethane
was
added under ice cooling a soloution of 2.18 g(8.84 mmol) of 3-chloroperbenzoic
acid (ca.
70 %) in 35 ml dichloromethane. After stirring for 1 h at 0 C, 2.6 g(25.7
mmol)
triethylamine were added slowly. The reaction mixture was concentrated to a
total volume
of 10 mL and the residue was purified by flash-chromatography. The crude
material was
suspended in 20 ml diethyl ether, filtered and dried in vacuo to give 4.2 g(82
%) of the title
compound as white crystals. M.p. 149-151 C (partial decomposition).
MS m/e (%): 582 (M+H+, 100).
Example 2
2- (3,5-Bis-trifluoromethyl-phenyl)-N- [4-(2-chloro-phenyl)-6- (4-oxy-
morpholin-4-yl)-
3o pyridin-3-yl]-N-methyl-isobutyramide
The title compound was obtained as white crystals in comparable yields
according to the
procedures described above for Example 1 using 2-chlorophenylboronic acid
instead of o-
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tolylboronic acid in step d). M.p.141-143 C (partial decomposition),
MS m/e (%): 602 (M+H+, 100), 624 (M+Na+, 10).
Example 3
2-(3,5-Bis-trifluoromethyl-phenyl)-N-,[6- (4-oxy-morpholin-4-yl)-4-o-tolyl-
pyridin-3-yl] -
isobutyramide
The parent compound was obtained as white powder in comparable yields
according to the
procedures described above for the preparation of Example 1 in steps a) to g).
Step f) was
omitted.
MS m/e (%): 552 (M+H}, 100).
1o The N-oxide was obtained in accordance with step h) in Example 1.
Example 4
2- (3,5-Bis-trifluoromethyl-phenyl)-N- [4'-(2-chloro-phenyl)-1-oxy-3,4,5,6-
tetrahydro-2H-
[ 1,2']bipyridinyl-5'-yl]-N-methyl-isobutyramide
The parent compound was obtained as a white powder in comparable yields
according to
the procedures described above for the preparation of Example 1 in steps a) to
g) using
piperidine instead of morpholine in step a) and using 2-chlorophenylboronic
acid instead
of o-tolylboronic acid in step d).
MS m/e ( fo): 583 (M+, 20),296 (78), 255 (100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 5
2- (3,5-Bis-trifluoromethyl-phenyl)-N-(6-oxy-dimethylamino-4-o-tolyl-pyridin-3-
yl)-N-
methyl-isobutyramide
The parent compound was obtained as white solid in comparable yields according
to the
procedures described above for the preparation of Example 1, steps a) to g)
using
dimethylamine hydrochloride instead of morpholine in step a). M.p. 174-175 C,
MS m/e (%): 524 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 6
2- (3,5-Bis-trifluoromethyl-phenyl)-N- [4- (2-chloro-phenyl)-6-oxy-
dimethylamino-
3o pyridin-3-yl]-isobutyramide
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The parent compound was obtained as white solid in comparable yields according
to the
procedures described above for the preparation of Example 1 steps a) to g)
using
dimethylamine hydrochloride instead of morpholine in step a) and using 2-
chlorophenylboronic acid instead of o-tolylboronic acid in step d). M.p. 162-
163 C.
MS m/e (%): 544 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 7
2- ( 3,5-Bis-trifluoromethyl-phenyl)-N-1- (4-hydroxy-l-oxy-4'-o-tolyl-3,4,5,6-
tetrahydro-
2H- [ 1,2' ]bipyridinyl-5'-yl)-N-methyl-isobutyramide
lo The parent compound was obtained as white foam in comparable yields
according to the
procedures described above for the preparation of Example 1 steps a) to g)
using 4-
hydroxypiperidine instead of morpholine in step a).
MS m/e (%): 580 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 8
2- (3,5-Bis-trifluoromethyl-phenyl)-N-{6- [ (2-hydroxy-ethyl)-1-oxy-methyl-
amino]-4-o-
tolyl-pyridin-3-yl}-N-rnethyl-isobutyramide
The parent compound was obtained as white foam in comparable yields according
to the
procedures described above for the preparation of Example 1 in steps a) to g)
using N-
methylethanolamine instead of morpholine in step a).
MS m/e (%): 554 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 9
(R)-2-(3,5-Bis-trifluoromethyl-phenyl)-N- [6-(3-hydroxy-l-oxy-pyrrolidin-1-yl)-
4-o-
tolyl-pyridin-3-yl] -N-methyl-isobutyramide
The parent compound was obtained as white foam in comparable yields according
to the
procedures described above for the preparation of Example 1 in steps a) to g)
using (R)-3-
hydroxypyrrolidine instead of morpholine in step a).
MS m/e (%): 566 (M+H+, 100).
3o The N-oxide was obtained in accordance with step h) in Example 1.
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Example 10
2-(3,5-Bis-trifluoromethyl-phenyl)-N-methyl-N- [6-(4-oxy-morpholin-4-yl)-4-o-
tolyl-
pyridin-3-yl] -acetamide
To a solution of 300 mg (1.1 mmol) 3,~-bis(trifluoromethyl)-phenylacetic acid
in 7 ml
N,N-dimethylformamide were added 185 mg (1.14 mmol) 1,1`-carbonyl-diimidazole
and
the solution was stirred for 30 min at room temperature. After addition of 283
mg (1
mmol) of inethyl-(6-morpholin-4-yl-4-tolyl-pyridin-3-yl)-amine (as described
in step f)
for the preparation of Example 1), the reaction mixture was heated over night
at 90 C.
After cooling to room temperature, the solvent was removed in vacuo and the
residue was
1o re-dissolved in 30 ml ethyl acetate. The organic phase was washed with
water (2 x 30 ml),
brine, dried (magnesium sulfate) and evaporated. Flash chromatography gave 506
mg (94
%) of the parent compound as a light brown foam.
MS m/e (%): 538 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 11
2-(3,5-Dimethoxy-phenyl)-N-methyl-N- [6-(4-oxy-morpholin-4-yl)-4-o-tolyl-
pyridin-3-
yl] - acetamide
To a solution of 226 mg (1.15 mmol) 3,5-dimethoxy-phenylacetic acid in 7 ml
N,N-
dimethylformamide were added 244 mg (1.5 mmol) 1,1`-carbonyl-diimidazole and
the
solution was stirred for 30 min at room temperature. After addition of 283 mg
(1 mmol) of
methyl-(6-morpholin-4-yl-4-tolyl-pyridin-3-yl)-amine (as described in step f)
for the
preparation of Example 1), the reaction mixture was heated at 70 C for 7h.
After cooling
to room temperature, the solvent was removed in vacaio and the residue was re-
dissolved in
ml ethyl acetate. The organic phase was washed with water (2 x 30 ml), brine,
dried
25 (magnesium sulfate) and evaporated. Flash chromatography gave 347 mg (75 %)
of the
parent compound as a white foam.
MS m/e (%): 462 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
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Example 12
2-(3-Fluoro=5-trifluoromethyl-phenyl)-N-methyl-N- [6-(4-oxy-morpholin-4-yl)-4-
o-tolyl-
pyridin-3-yl]- acetamide
To a solution of 266 mg (1.2 mmol) 3-puoro-5-trifluoromethyl-phenylacetic acid
in 7 ml
N,N-dimethylformamide were added 195 mg (1.2 mmol) 1,1`-carbonyl-diimidazole
and
the solution was stirred for 30 min at room temperature. After addition of 283
mg (1
mmol) of inethyl-(6-morpholin-4-yl-4-tolyl-pyridin-3-yl)-amine (as described
in step f)
for the preparation of Example 1), the reaction mixture was heated at 90 C
for 6h. After
cooling to room temperature, the solvent was removed in vacuo and the residue
was re-
dissolved in 30 ml ethyl acetate. The organic phase was washed with water (2 x
30 ml),
brine, dried (magnesium sulfate) and evaporated. Flash chromatography gave 432
mg (88
%) of the parent compound as a light yellow foam.
MS m/e (%): 488 (M+H}, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 13
4-15- [ (3,5-Bis-trifluoromethyl-benzyl)-methyl-carbamoyl] -4-o-tolyl-pyridin-
2-yl}-4-oxy-
piperazine-1-carboxylic acid tert-butyl ester
a) 6-Chloro-N-methyl-4-o-tolyl-nicotinamide
To a solution of 3.41 g(20.0 mmol) 6-chloro-N-methyl-nicotinamide in 80 ml
tetrahydrofuran 50 ml (50 mmol) of a 1 M solution of o-tolyl magnesium
chloride in
tetrahydrofuran was added dropwise at 0 C. After completed addition the
reaction
mixture was allowed to warm to room temperature and stirred for 1.5h. The
mixture was
again cooled to 0 C, followed by the dropwise addition of 5.7 ml (100 mmol)
acetic acid
and a solhrtion of 5.1 g(22 mmol) 2,3-dichloro-5,6-dicyano-1,4-benzoquinone in
18 ml
tetrahydrofuran. After completed addition the reaction mixture was allowed to
warm to
room temperature and stirred for 15 min. Addition of 30 m12 N aqueous sodium
hydroxide solution was followed by dilution with 11 ethyl acetate and 200 ml
water. The
layers were separated and the organic layer was washed with 4 250-m1 portions
of 2 N
aqueous sodium hydroxide solution. The combined aqueous layers were extracted
with 3
500-m1 portions of ethyl acetate. The combined organic extracts were washed
with
saturated aqueous sodium chloride solution and dried with sodium sulfate.
Concentration
gave 5.44 g of a brown-red oil. Flash column chromatography afforded 2.15
g(41.3 %) of
the title compound as a light yellow solid.
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MS m/e (%): 260 (M+, 11), M.p. 91- 93 C.
b) 4-(5-Methylcarbamoyl-4-o-tol rl-pyridin-2 -yl)-piperazine-l-carboxylic acid
tert-butyl
ester
A mixture of 8.31 g(31.9 mrnol) 6-chloro-N-methyl-4-o-tolyl-nicotinamide, 6.53
g(35.0
mmol) 1-tert-butoxycarbonyl piperazine, 16.7 ml (95.6 mmol) N-
ethyldiisopropylamine
and a catalytic amount of 4-(N,N-dimethylamino)-pyridine was heated at reflux
over
night. After cooling to room temperature the mixture was dissolved in
dichloromethane
and washed with two portions of 0.1 N aqueous hydrochloric acid solution.
Drying with
sodium sulfate and concentration gave 10.7 g of the crude product. Flash
column
1o chromatography afforded 6.28 g(48.0 %) of the title compound as an off-
white solid.
MS m/e (%): 411 (M+H +, 100).
cl 4-15- [ (3,5-Bis-trifluoromethyl-benzyl)-methyl-carbamoyll -4-o-tolyl-
pyridin-2-yll-
piperazine-l-carboxylic acid tert-buMl ester
To a solution of 6.28 g(15.3 mmol) 4-(5-methylcarbamoyl-4-o-tolyl-pyridin-2-
yl)-
piperazine-l-carboxylic acid tert-butyl ester in 250 ml tetrahydrofiiran 20 ml
of a 1 M
solution (20 mmol) of potassium hexamethyldisilazide in tetrahydrofuran were
added at 0
C. After 30 min, 2.81 ml (15.3 mmol) 3,5-bis(trifluoromethyl)benzyl bromide
were added
dropwise. The reaction mixture was allowed to warm to room temperature over
night.
Addition of water and 1 M aqueous sodium hydroxide solution was followed by
extraction
with three portions of ethyl acetate. The combined organic extracts were dried
with sodium
sulfate and concentrated. Flash column chromatography gave 6.89 g(70.8 %) of
the parent
compound as a white solid.
MS m/e (%): 637 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 14
5'- [ (3,5-Bis-trifluoromethyl-benzyl)-methyl-carbamoyl] -4'-o-tolyl-l-oxy-
3,4,5,6-
tetrahydro-2H-[1,2']bipyridinyl-4-carboxylic acid ethyl ester
The parent compound was obtained as a white solid in comparable yields
according to the
procedures described above for the preparation of 4-{5-[(3,5-bis-
trifluoromethyl-benzyl)-
methyl-carbamoyl]-4-o-tolyl-pyridin-2-yl}-piperazine-l-carboxylic acid tert-
butyl ester
(Example 13) using ethyl isonipecotate instead of 1-tert-butoxycarbonyl
piperazine in step
b) and using 5'-methylcarbamoyl-4'-o-tolyl-3,4,5,6-tetrahydro-2H-
[1,2']bipyridinyl-4-
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carboxylic acid ethyl ester instead of 4-(5-methylcarbamoy1-4-o-tolyl-pyridin-
2-yl)-
piperazine-1 -carboxylic acid tert-butyl ester in step c).
MS m/e (%): 608 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
; Example 15
( RS )-6- [ 3- (Acetyl-methyl-amino ) -1-oxo-pyrrolidin-l-yl] -N- (3,5-bis-
trifluorornethyl-
benzyl)-N-methyl-4-o-tolyl-nicotinamide
The parent compound was obtained as a light-yellow solid in comparable yields
according
to the procedures described above for the preparation of 4-15-[(3,5-bis-
trifluoromethyl-
1o benzyl)-methyl-carbamoyl]-4-o-tolyl-pyridin-2-yl}-piperazine-l-carboxylic
acid tert-butyl
ester (Example 13) using (RS)-3-(acetyl-methyl-amino)-pyrrolidine instead of 1-
tert-
butoxycarbonyl piperazine in step b) and using (RS)-6-[3-(acetyl-methyl-amino)-
pyrrolidin-l-yl]-N-methyl-4-o-tolyl-nicotinamide instead of 4-(5-
methylcarbamoyl-4-o-
tolyl-pyridin-2-yl)-piperazine-1-carboxylic acid tert-butyl ester in step c).
MS m/e (%): 593 (M+H +, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 16
N- (3,5-Bis-trifluoromethyl-benzyl)-N-methyl-6- (4-oxy-morpholin-4-yl)-4-o-
tolyl-
nicotinamide monohydrate
2o a) 6-Chloro-N-methyl-nicotinamide
To 50 g(317 mmol) of 2-chloronicotinic acid were added 230 ml (3.16 mol)
thionyl
chloride at 0 C. After heating the mixture at reflux for 2 h excess thionyl
chloride was
removed by distillation. The oily brown residue was dissolved in 250 ml
dichloromethane.
The solution was treated with methylamine gas at 0 C until no exothermic
reaction was
observed any longer. The resulting suspension was diluted with 1000 ml
dichloromethane/water. The layers were separated and the aqueous layer
extracted with
three 300-m1 portions of dichloromethane. Drying of the combined organic
layers with
sodium sulfate and concentration gave 53.2 g(98 %) of the title compound as a
light
yellow solid.
MS m/e (%): 171 (M+H+, 15).
b) 6-Chloro-N-methy1-4-o-tolyl-nicotinamide
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To a solution of 3.41 g(20.0 mmol) 6-chloro-N-methyl-nicotinamide in 80 ml
tetrahydrofuran 50 ml (50 mmol) of a 1 M solution of o-tolyl magnesium
chloride in
tetrahydrofuran was added dropwise at 0 C. After completed addition the
reaction
mixture was allowed to warm to room temperature and stirred for 1.5 h. The
mixture was
again cooled to 0 C, followed by the dropwise addition of 5.7 ml (100 mmol)
acetic acid
and a solution of 5.1 g(22 mmol) 2,3-dichloro-5,6-dicyano-1,4-benzoquinone in
18 ml
tetrahydrofuran. After completed addition the reaction mixture was allowed to
warm to
room temperature and stirred for 15 min. Addition of 30 m12 N aqueous sodium
hydroxide solution was followed by dilution with 11 ethyl acetate and 200 ml
water. The
1o layers were separated and the organic layer was washed with 4 250-m1
portions of 2 N
aqueous sodium hydroxide solution. The combined aqueous layers were extracted
with 3
500-m1 portions of ethyl acetate. The combined organic extracts were washed
with
saturated aqueous sodium chloride solution and dried with sodium sulfate.
Concentration
gave 5.44 g of a brown-red oil. Flash column chromatography afforded 2.15
g(41.3 %) of
the title compound as a light yellow solid. M.p. 91-93 C.
MS m/e (%): 260 (M+, 11).
c N-Methyl-6-morpholin-4-yl-4-o-tolyl-nicotinamide
A mixture of 1.00 g(3.84 mmol) 6-chloro-N-methyl-4-o-tolyl-nicotinamide, 0.37
ml (4.22
mmol) morpholine, 2.0 ml (12 mmol) N-ethyldiisopropylamine and a catalytic
amount of
2o 4- (N,N-dimethylamino) -pyridine was heated at 100 C over night. After
cooling to room
temperature the mixture was dissolved in ethyl acetate and washed with two
portions of
water. The combined aqueous layers were extracted with 3 portions of
dicbloromethane.
Drying with sodium sulfate and concentration gave 1.23 g of the crude product.
Flash
column chromatography afforded 1.11 g(92.9 %) of the title compound as an off-
white
solid. M.p. 156-158 C.
MS m/e (%): 311 (M +, 64).
d) N-(3,5-Bis-trifluorometh 1-y benzyl)-N-methyl-6-morpholin-4-yl-4-o-tolyl-
nicotinamide
To a solution of 0.27 g(0.87 mmol) N-methyl-6-morpholin-4-yl-4-o-tolyl-
nicotinamide in
15 ml tetrahydrofuran, 1.12 ml of a 1 M solution (1.12 mmol) of potassium
hexamethyldisilazide in tetrahydrofuran was added at 0 C. After 30 min, 0.16
ml (0.87
mmol) 3,5-bis(trifluoromethyl)benzyl bromide were added dropwise and the
reaction
mixture was allowed to warm to room temperature over night. Quenching with
water was
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followed by extraction with ethyl acetate. The combined organic extracts were
dried with
sodium sulfate and concentrated. Column chromatography gave 0.20 g(44 %) of
the title
compound as a white solid.
MS m/e (%): 538 (M+H+, 100).
e) N-(3,5-Bis-trifluoromethyl-benzyl)-N-methyl-6-(4-oxy-morpholin-4-yl)-4-o-
tolyl-
nicotinamide monohydrate
To a solution of 0.40 g(0.74 mmol) N-(3,5-bis-trifluoromethyl-benzyl)-N-methyl-
6-
morpholin-4-yl-4-o-tolyl-nicotinamide in 4 ml dichloromethane 0.17 g 3-
chloroperbenzoic acid (70 %; 0.71 mmol) were added at 0 C. After 4h the
reaction
1o mixture was diluted with dichloromethane and washed with 3 portions of
saturated
sodium carbonate solution. The combined aqueous layers were extracted with
dichloromethane. The combined organic extracts were washed with saturated
sodium
chloride solution, dried with sodium sulfate and concentrated. Column
chromatography
gave 0.31 g(73 %) of the title compound as a white solid.
MS m/e (%): 534 (M+H+, 100).
Crystallisation of a portion of 100 mg from a mixture of t-butylmethyl ether
and
cyclohexane afforded 90 mg of the title compound as white crystals. M.p. 116-
117 C.
Example 17
N-(3,5-Bis-trifluoromethyl-benzyl)-6-(1,1-dioxo-1 X 6-4-oxy-thiomorpholin-4-
yl)-N-
methyl-4-o-tolyl-nicotinamide
a) N435-Bis-trifluoromethy1-benMXl)-N-methyl-6-thiomorpholin-4-yl-4-o-tolyl-
nicotinamide
The title compound was obtained as a white solid in comparable yields
according to the
procedures described above for the preparation of 4-{5-[(3,5-bis-
trifluoromethyl-benzyl)-
methyl-carbamoyl]-4-o-tolyl-pyridin-2-yl}-piperazine-l-carboxylic acid tert-
butyl ester
using thiomorpholine instead of 1-tert-butoxycarbonyl piperazine in step b)
and using N-
methyl-6-thiomorpholin-4-yl-4-o-tolyl-nicotinamide instead of 4-(5-
methylcarbamoyl-4-
o-tolyl-pyridin-2-yl)-piperazine-l-carboxylic acid tert-butyl ester in step
c).
MS m/e (%): 554 (M+H+, 100).
3o b) N-(3_,5-Bis-trifluoromethyl-benMXl)-N-methyl-6-(1-oxo-1),4-thiomorpholin-
4-yl)-4-o-
tolyl-nicotinamide
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To a solution of 1.24 g(2.24 mmol) N-(3,5-bis-trifluororriethyl-benzyl)-N-
methyl-6-
thiomorpholin-4-yl-4-o-tolyl-nicotinamide (step a)) in 25 ml methanol were
added 689
mg (1.12 mmol) Oxone at 0 C. After completed addition the reaction mixture
was
allowed to warm to room temperature and stirred for 1.5 h. Quenching with 5
m140%
aqueous sodium hydrogen sulfite solution was followed by addition of 6 m11N
sodium
~
hydroxide solution to adjust the pH to 7-8. The mixture was diluted with 50 ml
water and
extracted with 3 150-m1 portions of dichloromethane. The combined extracts
were dried
with sodium sulfate and concentrated to give 1.20 g of crude product. Flash
chromatography afforded 1.02 g(79.9 %) of the title compound as a white solid.
lo MS m/e (%): 570 (M+H+, 100).
c) N-(3,5-Bis-trifluoromethyl-benzyl)-6-(1,1-dioxo-1k6-thiomorpholin-4-yl)-N-
methyl-4-
o-tolyl-nicotinamide
The parent compound was obtained as a white solid in comparable yield
according to the
procedure described above (step b)) using N-(3,5-bis-trifluoromethyl-benzyl)-N-
methyl-
6-(1-oxo-1X4-thiomorpholin-4-yl)-4-o-tolyl-nicotinamide instead of N-(3,5-bis-
trifluoromethyl-benzyl)-N-methyl-6-thiomorpholin-4-yl-4-o-tolyl-nicotinamide.
MS m/e (%): 586 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 18
2o N-(3,5-Bis-trifluoromethyl-benzyl)-6-(4-formyl-l-oxy-piperazin-l-yl)-N-
methyl-4-o-
tolyl-nicotinamide
To a mixture of 0.089 ml (1.1 mmol) N,N-dimethylformamide and 38 mg (0.56
mmol)
imidazole 0.071 ml (0.56 mmol) trimethylchlorosilane were added dropwise at
room
temperature. The reaction mixture was cooled to 0 C, and 0.10 g(0.19 mmol) N-
(3,5-bis-
trifluoromethyl-benzyl)-N-methyl-6-piperazin-l-yl-4-o-tolyl-nicotinamide were
added.
The ice-water bath was removed and the mixture stirred over night. The
reaction was
quenched with a mixture of 2 ml 1 N aqueous hydrochloric acid solution and 4
ml water,
and the mixture was extracted with ethyl acetate. The combined extracts were
dried with
sodium sulfate and concentrated. Flash column chromatography afforded 81 mg
(82 %) of
the parent compound as a white solid.
MS m/e (%): 565 (M+H +, 100).
The title compound was obtained in accordance with step h) in Example 1.
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Example 19
N-Methyl-N- (2-methyl-naphthalen-l-ylrnethyl)-6-(4-oxy-rnorpholin-4-yl)-4-o-
tolyl-
nicotinamide
a) N-Methyl-6-morpholin-4-yl-4-o-tolyl-nicotinamide
The title compound was obtained as an off-white solid in comparable yield
according to
the procedure described above for the preparation of 4-{5-[(3,5-bis-
trifluoromethyl-
benzyl)-methyl-carbamoyl)-4-o-tolyl-pyridin-2-yl}-piperazine-l-carboxylic acid
tert-butyl
ester (Example 13, step b) using morpholine instead of 1-tert-butoxycarbonyl
piperazine.
MS m/e (%): 311 (M }, 63).
io b) N-Methyl-N-(2-methyl-naphthalen-1- l~yl~-6-morpholin-4-yl-4-o-tolyl-
nicotinamide
The parent compound was obtained as a white solid in comparable yield
according to the
procedure described above for the preparation of N-(3,5-bis-trifluoromethyl-
benzyl)-N-
methyl-6-morpholin-4-yl-4-o-tolyl-nicotinamide (Example 16, step d) using 1-
chloromethyl-2-methylnaphthalene instead of 3,5-bis-trifluoromethyl-benzyl
bromide.
MS m/e (%): 466 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 20
N-Methyl-6-(4-oxy- morpholin-4-yl)-N-naphthalen-1-ylmethyl-4-o-tolyl-
nicotinamide
2o The parent compound was obtained as a colorless viscous oil in comparable
yields
according to the procedures described above for the preparation of N-methyl-N-
(2-
methyl-naphthalen-l-ylmethyl)-6-morpholin-4-yl-4-o-tolyl-nicotinamide (Example
19)
using 1-chloromethylnaphthalene instead of 1-chloromethyl-2-methylnaphthalene
in step
b).
MS m/e (%): 452 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 21
N- (2-Methoxy-naphthalen-l-ylmethyl)-N-methyl-6-(4-oxy-morpholin-4-yl)-4-o-
tolyl-
nicotinamide
3o The parent compound was obtained as a colorless viscous oil in comparable
yields
according to the procedures described above for the preparation of N-methyl-N-
(2-
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methyl-naphthalen-l-yl-methyl)-6-morpholin-4-yl-4-o-tolyl-nicotinamide
(Example 19)
using toluene-4-sulfonic acid 2-methoxy-naphthalen-1-yl-methyl ester instead
of 1-
chloromethyl-2-methylnaphthalene in step b).
MS m/e (%): 482 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 22
N-(2-Methoxy-benzyl)-N-methyl-6- (4-oxy-morpholin-4-yl)-4-o-tolyl-nicotinamide
The parent compound was obtained as a colorless viscous oil in comparable
yields
according to the procedures described above for the preparation of N-methyl-N-
(2-
lo methyl-naphthalen-l-yl-methyl)-6-morpholin-4-yl-4-o-tolyl-nicotinamide
(Example 19)
using 2-methoxy-benzyl chloride instead of 1-chloromethyl-2-methylnaphthalene
in step
b).
MS m/e (%): 432 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 23
N- ( 5-Chloro-2-methoxy-benzyl)-N-methyl-6- (4-oxy-morpholin-4-yl)-4-o-tolyl-
nicotinamide
The parent compound was obtained as a white solid in comparable yields
according to the
procedures described above for the preparation of N-methyl-N-(2-methyl-
naphthalen-1-
ylmethyl)-6-morpholin-4-yl-4-o-tolyl-nicotinamide (Example 19) using 5-chloro-
2-
methoxy-benzyl chloride instead of 1-chloromethyl-2-methylnaphthalene in step
b).
MS m/e (%): 466 (M+H }, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 24
N-(2-Chloro-5-methoxy-benzyl)-N-methyl-6-morpholin-4-yl-4-o-tolyl-nicotinamide
The parent compound was obtained as a white solid in comparable yields
according to the
procedures described above for the preparation of N-meth.yl-N-(2-methyl-
naphthalen-l-
ylmethyl)-6-morpholin-4-yl-4-o-tolyl-nicotinamide (Example 19) using 2-chloro-
5-
methoxy-benzyl bromide instead of 1-chloromethyl-2-methylnaphthalene in step
b).
MS m/e (%): 466 (M+H +, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
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Example 25
N-Methyl-6- (4-oxy-morpholin-4-yl)-N-pentafluorophenylmethyl-4-o-tolyl-
nicotinamide
The parent compound was obtained as a white solid in comparable yields
according to the
procedures described above for the preparation of N-methyl-N-(2-methyl-
naphthalen-l-
ylmethyl)-6-morpholin-4-yl-4-o-tolyl-nicotinamide (Example 19) using 2,3,4,5,6-
pentafluoro-benzyl bromide instead of 1-chloromethyl-2-methylnaphthalene in
step b).
MS m/e (%): 492 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 26
lo N-Methyl-6-(4-oxy-morpholin-4-yl)-N-naphthalen-2-ylmethyl-4-o-tolyl-
nicotinamide
The parent compound was obtained as a white solid in comparable yields
according to the
procedures described above for the preparation of N-methyl-N-(2-methyl-
naphthalen-l-
ylmethyl)-6-morpholin-4-yl-4-o-tolyl-nicotinamide (Example 19) using 2-
chloromethyl-
naphthalene instead of 1-chloromethyl-2-methylnaphthalene in step b).
MS m/e (%): 452 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 27
N- [2-Methoxy-5-(5-trifluoromethyl-tetrazol-l-yl)-benzyl] -N-methyl-6-(4-oxy-
morpholin-4-yl)-4-o-tolyl-nicotinamide
2o The parent compound was obtained as a white solid in comparable yields
according to the
procedures described above for the preparation of N-methyl-N-(2-methyl-
naphthalen-l-
ylmethyl)-6-morpholin-4-yl-4-o-tolyl-nicotinamide (Example 19) using toluene-4-
sulfonic acid [2-methoxy-5-(5-trifluoromethyl-tetrazol-1-yl)-phenyl]-methyl
ester instead
of 1-chloromethyl-2-methylnaphthalene in step b).
MS m/e (%): 568 (M+H +, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
Example 28
N-(1,4-Dimethoxy-naphthalen-2-ylmethyl)-N-methyl-6-(4-oxy-morpholin-4-yl)-4-o-
tolyl-nicotinamide
The parent compound was obtained as a colorless viscous oil in comparable
yields
according to the procedures described above for the preparation of N-methyl-N-
(2-
methyl-naphthalen-l-ylmethyl)-6-morpholin-4-yl-4-o-tolyl-nicotinamide (Example
19)
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using 2-chloromethyl-1,4-dimethoxy-naphthalene instead'of 1-chloromethyl-2-
methylnaphthalene in step b).
MS m/e (%): 512 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example l.
IExample 29
5'- [ ( 3,5-Bis-trifluoromethyl-benzyl)-methyl-carbamoyl] -4'-o-tolyl-l-oxy-
3,4,5,6-
tetrahydro-2H-[1,2']bipyridinyl-4-carboxylic acid
A mixture of 200 mg (0.33 mmol) 5'-[(3,5-bis-trifluoromethyl-benzyl)-methyl-
carbamoyl]-4'-o-tolyl-3,4,5,6-tetrahydro-2H-[1,2']bipyridinyl-4-carboxylic
acid ethyl ester
(Example 14), 10 ml 1N aqueous sodium hydroxide solution and 10 ml methanol
was
stirred at room temperature over night. After washing with 2 portions of ethyl
acetate the
aqueous layer was acidified to pH 4 with 1 N aqueous hydrochloric acid
solution.
Extraction with dichlorometharie, drying with sodium sulfate and flash column
chromatography afforded 81 mg (42 %) of the parent compound as a white solid.
MS m/e (%): 580 (M+H+, 100).
The N-oxide was obtained in accordance with step h) in Example 1.
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Example A
Tablets of the following composition are manufactured in the usual manner:
m /tg ablet
Prodrug 5
Lactose 45
Corn starch 15
Microcrystalline cellulose 34
Magnesium stearate 1
Tablet weight 100
lo Example B
Capsules of the following composition are manufactured:
mg/capsule
Prodrug 10
Lactose 155
Corn starch 30
Talc 5
Capsule fill weight 200
The active substance, lactose and corn starch are firstly mixed in a mixer and
then in
a comminuting machine. The mixture is returned to the mixer, the talc is added
thereto
2o and mixed thoroughly. The mixture is filled by machine into hard gelatine
capsules.
Example C
Suppositories of the following composition are manufactured:
m /sg upp.
Prodrug 15
Suppository mass 1285
Total 1300
The suppository mass is melted in a glass or steel vessel, mixed thoroughly
and
cooled to 45 C. Thereupon, the finely powdered active substance is added
thereto and
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stirred until it has dispersed completely. The mixture is poured into
suppository moulds of
suitable size, left to cool, the suppositories 'are then removed from the
moulds and packed
individually in wax paper or metal foil.
